Electronically non-adiabatic transitions in high-energy CH3I+CH3I collisions computed by the quantal FMS method using the Evans-Polanyi potential

The effective energy threshold for the crossing into an electronically exci ted state and the post threshold rise of the yield of crossing are discusse d. The time-dependent Schrodinger equation for multiple electronic states i s solved using the full multiple spawning (FMS) methodology. The quantal re sults are compared with classical path methods. The potential energy functi on is of the LEP form including the electronically excited surface. For kin ematic reasons, the yield is exponentially small until an effective thresho ld, at similar to 10 km s(-1), with a steep rise of the yield in the post t hreshold regime. (C) 1999 Elsevier Science B.V. All rights reserved.